1. Field of the Invention
The present application relates generally to apparatus and methods of image scanning.
2. Description of the Background Art
Scanner devices, such as a flatbed scanner, produce machine-readable image data signals that are representative of a scanned two-dimensional object, typically a photograph or a page of printed text. In a typical scanner application, the image data signals produced by a flat bed scanner may be used by a computer system to reproduce an image of the scanned two-dimensional object on a suitable display device, such as a cathode ray tube (“CRT”) or liquid crystal display (“LCD”). The computer system may also print an image of the two-dimensional object on a printer connected to the computer system.
One recent feature of modern scanners is a capability to perform dust and scratch removal from transparent substrates, such as 35 mm slides and negatives. This feature is typically accomplished by scanning the transparency with both conventional visible lighting, and then again with an infrared illumination source. Since the dust and scratches typically appear opaque to infrared illumination, they appear quite distinctly in the resulting infrared image. A mask may be computed from this infrared image that identifies which pixels in the scan have dust and scratch imperfections. Once these pixels are labeled, they may be replaced using “in-filling” and/or “in-painting” methods correcting these imperfections in the resultant scanned image.
It is highly desirable to improve capabilities of scanner devices and image scanning systems.